divisors(900)
[1, 2, 3, 4, 5, 6, 9, 10, 12, 15, 18, 20, 25, 30, 36, 45, 50, 60, 75, 90, 100, 150, 180, 225, 300, 450, 900]
sum(divisors(900))
2821
number_of_divisors(900)
27
number_of_divisors(900) == len(divisors(900))
True